Thanks Dave, but there's no other drive in my iMac or connected to my iMac except the internal HD with Snow Leopard and the OWC Mercury Elite drive with a Super Duper clone of my internal connected with Firewire 800.

I guess I should give it another try. If I start with my iMac shutdown and with my peripheral drive powered up, and then power up my iMac and hold down the option key just as I hear the gong it theoretically should work, right? In this scenario, when should I release the option key?